Much of the campaign centered on immigration, where critics on both sides have recently taken aim at Cantor.

Brat has accused the House majority leader of being a top cheerleader for "amnesty" for immigrants in the U.S. illegally. Cantor has responded forcefully by boasting in mailers of blocking Senate plans "to give illegal aliens amnesty."

It was a change in tone for Cantor, who has repeatedly voiced support for giving citizenship to certain immigrants brought illegally to the country as children. Cantor and House GOP leaders have advocated a step-by-step approach rather than the comprehensive bill backed by the Senate. They've made no move to bring legislation to a vote and appear increasingly unlikely to act this year.

“Amnesty is very bad for the country,” Coulter told Kelly.

Of Brat’s win, she said, “I hope it will at least shut down any more happy talk about amnesty this year, I wish it would have the effect of Republicans waking up and seeing that this is a winning issue for the Republicans, and not just the Republican base."